a plant without cotyledons, therefore one belonging to a group lower than the seed plants.
Origin of acotyledon
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
any plant, such as a fern or moss, that does not possess cotyledons
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012